Resorbable anchor arrangements for implantable devices and methods of making and using

ABSTRACT

An implantable device includes a device body and at least one anchoring unit configured and arranged for anchoring the device body in a patient upon implantation. The anchoring unit includes a resorbable material that resorbs into the patient over a period of time after implantation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of U.S. patent applicationSer. No. 11/376,360 filed on Mar. 15, 2006, which is incorporated hereinby reference.

FIELD

The invention is directed to implantable devices that include resorbableanchor arrangements, and methods of making and using the devices. Inaddition, the invention is directed to implantable leads having one ormore resorbable anchor arrangements and methods of making and using theleads.

BACKGROUND

Implantable electrical stimulation devices have proven therapeutic in avariety of diseases and disorders. For example, pacemakers andimplantable cardiac defibrillators have proven effective in thetreatment of cardiac conditions. Spinal cord stimulation systems havebeen used as a therapeutic modality for the treatment of chronic painsyndromes. Deep brain stimulation has also been useful for treatingrefractory chronic pain syndromes and has been applied to treat movementdisorders and epilepsy. Peripheral nerve stimulation has been used totreat chronic pain syndrome and incontinence, with a number of otherapplications under investigation. Functional electrical stimulationsystems have been applied to restore some functionality to paralyzedextremities in spinal cord injury patients.

Implantable drug delivery systems allow highly concentrated drugs to bedelivered to specific sites. This site specific delivery can result inreduced side effects, improved quality of life, and, in some cases, mayextend life. Such drug delivery systems include both programmable pumpsand constant flow pumps. Examples of such systems include intrathecaldrug delivery for the treatment of chronic intractable pain; delivery ofbaclofen for the treatment of spasticity; site specific delivery ofdrugs for the treatment of cancer, and site specific insulin deliveryfor the management of diabetes.

One disadvantage of these devices is that the electrode lead or drugcatheter may migrate within the body. Migration may result in failure ofthe therapy or unwanted side effects. A variety of methods have beenused to fix the lead or catheter including sutures and cuffs. While suchfixation can be useful to prevent or reduce lead or catheter migration,many leads and catheters are eventually removed due to, for example,patient request, therapy completion or failure, infection, etc. Thesefixation methods can make removal of the implantable device moredifficult.

BRIEF SUMMARY

One embodiment is an implantable device that includes a device body andat least one anchoring unit configured and arranged for anchoring thedevice body in a patient upon implantation. The anchoring unit includesa resorbable material that resorbs into the patient over a period oftime after implantation.

Another embodiment is a method of implanting a device. The methodincludes implanting an implantable device body and coupling an anchoringunit to tissue. The anchoring unit allows fixation of the device body tothe tissue. The anchoring unit includes resorbable material.

Yet another embodiment is an implantable device that includes a controlunit, an implantable device body combined with the control unit andconfigured and arranged to be implanted proximate to selected tissue ina patient, and at least one anchoring unit configured and arranged foranchoring the implantable device body in the patient upon implantation.The anchoring unit includes a resorbable material that resorbs into thepatient over a period of time after implantation.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the present invention aredescribed with reference to the following drawings. In the drawings,like reference numerals refer to like parts throughout the variousfigures unless otherwise specified.

For a better understanding of the present invention, reference will bemade to the following Detailed Description, which is to be read inassociation with the accompanying drawings, wherein:

FIG. 1 is a schematic perspective view of one embodiment of animplantable device with a resorbable anchor arrangement, according tothe invention;

FIG. 2 is a schematic perspective view of another embodiment of animplantable device with a resorbable anchor arrangement, according tothe invention;

FIG. 3 is a schematic perspective view of a third embodiment of animplantable device with a resorbable anchor arrangement, according tothe invention;

FIG. 4 is a schematic perspective view of a fourth embodiment of animplantable device with a resorbable anchor arrangement, according tothe invention;

FIG. 5 is a schematic perspective view of the implantable device of FIG.4 disposed over a nerve;

FIG. 6 is a schematic perspective view of the implantable device of FIG.4 with the resorbable anchor arrangement removed;

FIG. 7 is a schematic perspective view of the implantable device of FIG.4 disposed over a nerve and with the resorbable anchor arrangementremoved;

FIG. 8 is a schematic perspective view of a fifth embodiment of animplantable device with a resorbable anchor arrangement wrappedhelically around a nerve, according to the invention; and

FIG. 9 is a schematic perspective view of the implantable device of FIG.8 with the resorbable anchor arrangement removed.

DETAILED DESCRIPTION

The invention is directed to implantable devices that include resorbableanchor arrangements, and methods of making and using the devices. Inaddition, the invention is directed to implantable leads having one ormore resorbable anchor arrangements and methods of making and using theleads.

Suitable implantable devices include, but are not limited to, electrodeleads, catheters, sensors, and transmitters. For example, theimplantable device can be an electrode lead with one or more electrodesdisposed on a distal end of the lead and one or more terminals disposedon a proximal end of the lead. One embodiment of a resorbable anchorarrangement includes the electrodes disposed on the resorbable material.In another embodiment, the resorbable anchor arrangement can be disposedaround or attached to the electrode lead. Electrodes leads include, forexample, percutaneous leads and paddle leads. Examples of stimulatorsystems with electrode leads are found in U.S. Pat. Nos. 6,181,969;6,516,227; 6,609,029; 6,609,032; and 6,741,892; and U.S. patentapplication Ser. No. 11/238,240, all of which are incorporated byreference.

A resorbable anchor arrangement can also be used to fix amicrostimulator in place. Examples of suitable microstimulators aredescribed in U.S. Pat. Nos. 5,193,539; 5,193,540; 5,312,439; 6,051,017;and 6,609,032; U.S. Patent Application Publication No. 2004/059392; U.S.patent application Ser. Nos. 11/040,209 and 11/056,762; and PCT PatentApplications Publication Nos. 98/37926; 98/43700; and 98/43701, all ofwhich are incorporated herein by reference. The BION™ microstimulator,available from Advanced Bionics Corporation, Sylmar, Calif., is anexample of a microstimulator.

A resorbable anchor arrangement can also be used to fix a catheter inplace. For example, the catheter can be a portion of an implantable drugdelivery system. The catheter is typically implanted in the proximity ofthe tissue to be treated.

Implantable sensors can also be fixed using a resorbable anchorarrangement. Examples of sensors include, but are not limited to,electrical activity sensors (e.g., electroencephalograph,electrocardiograph, electromygraph, and electronystagmograph sensors);chemical sensors (e.g., glucose and drug sensors); and mechanicalactivity sensors (e.g., pressure, strain, stress, position, velocity,and acceleration sensors.)

These types of implantable devices can also be combined. For example, anelectrode lead may also include a catheter lumen to provide drugs orother medications to the tissue to be stimulated or to other proximatetissue. As another example, an electrode lead can include one or more ofthe sensors described above. Yet another example is a catheter thatincludes one or more of the above-described sensors.

The resorbable anchor arrangement allows the implantable device to befixed to the tissue at the implantation site using, for example,sutures, staples, and adhesive, or by at least partially wrapping theresorbable anchor arrangement around the tissue, for example, as a cuffor as a ribbon wrapped around a portion of a nerve, vein, artery,muscle, ligament, or organ. The resorbable material of the anchorarrangement is resorbed by the body of the patient over time. Theresorbtion typically releases, at least partially, the implantabledevice from the anchor arrangement. This release can assist in the laterremoval of the implantable device. In some instances, the implantabledevice may even be withdrawn from the implantation site by pulling onthe device (e.g., on an electrode lead or catheter.)

The resorbtion time for the resorbable material can be selected, ifdesired, to provide an average lifetime for the anchoring arrangement.For example, the resorbtion material may have an average resorbtion timeof 1 week, 1 month, 6 months, 1 year, 2 years, 5 years, 10 years, orlonger. The selection of a resorbtion time can be based on one or morefactors such as, for example, the implantable device, the site ofimplantation, the expected lifetime of the implantable device, theexpected duration of implantation, the age of the patient, expectedgrowth rate of tissue around the implanted device, and the expectedmaturation rate of the capsule surrounding device. It will be recognizedthat there may be substantial variation from the average resorbtion timein actual devices. The actual resorbtion time may depend on theconditions within the patient's body.

Examples of suitable resorbable material include, but are not limitedto, polylactide (PLA), polyglycolide (PGA), poly(lactide-co-glycolide)(PLGA), poly(e-caprolactone), polydioxanone, polyanhydride, trimethylenecarbonate, poly(β-hydroxybutyrate), poly(g-ethyl glutamate), poly(DTHiminocarbonate), poly(bisphenol A iminocarbonate), poly(ortho ester)s(POEs), polycyanoacrylate, polyphosphazene, modified polysaccharides(for example, cellulose, chitin, dextran), and modified proteins (forexample, fibrin, casein).

In some embodiments, the resorbable anchor arrangement may also have adrug, medication, tissue growth enhancer, or other agent disposed in theresorbable material for time release. For example, the resorbablematerial may be combined with a drug or other medication to treat thetissue at the implantation site or to reduce pain or inflammation. Asanother example, the resorbable material may be combined with asubstance that promotes tissue growth and encapsulation of at least aportion of the implantable device. Generally, the drug, medication, orother agent is released over time as the resorbable material is resorbedby the patient's body.

In at least some embodiments, the anchoring arrangement is configured toenhance tissue fixation of the implantation device, to replace theanchoring arrangement, as the material is resorbed into the body of thepatient. As indicated above, the anchoring arrangement may include asubstance that promotes tissue growth or encapsulation. Additionally oralternatively, the shape of the anchoring arrangement may promoteencapsulation; the anchoring arrangement may include grooves or poresthat promote tissue in-growth to stabilize the implantable device inplace; or the shape may have a three-dimensional structure that providesa scaffold to enhance and guide the direction of tissue growth. In atleast some instances, the implantable device may be later removed orexplanted by pulling on the device. The device preferably follows a pathalong the encapsulating tissue. This procedure, preferably, reducestissue damage that would occur if the implantable device were otherwiseremoved.

FIGS. 1-3 illustrate embodiments of one type of anchoring arrangement.This type of anchoring arrangement 102 a, 102 b, 102 c fits around aportion of an implantable device, such as an electrode lead 104 (or acatheter, sensor, or transmitter.) The anchoring arrangement is at leastpartially, and preferably fully, formed of resorbable material. Theanchoring arrangement can be formed integrally with the implantabledevice or the anchoring arrangement can be a separate component that canbe slid onto or otherwise attached to the implantable device. In oneembodiment, the anchoring arrangement is made to fit onto an existingimplantable device. This can allow a practitioner or other to retrofitexisting implantable devices. These anchoring arrangements 102 a, 102 b,102 c can be sutured, stapled, glued, or otherwise attached to thetissue of the patient to fix the implantable device in place duringimplantation.

The anchoring arrangement 102 a of FIG. 1 fits around the electrode lead104 so that a suture 106 or other fastener (e.g., a staple) can passbetween the body of the anchoring arrangement and the lead to allowfixation of the lead to the surrounding tissue. In the illustratedexample, the anchoring arrangement 102 a is a ring of material, however,it will be recognized that other shapes can also be used. As theanchoring arrangement is resorbed into the body of the patient, thesuture is released. The suture 106 is optionally formed of resorbablematerial.

The anchoring arrangement 102 b of FIG. 2 includes one or more openings108 through which a suture 106 or other fastener (e.g., a staple) canpass to allow fixation of the lead to the surrounding tissue. Althoughthe anchoring arrangement 102 b is illustrated as a separate componentthat can be slid onto the lead 104, it will be recognized that theanchoring arrangement can also be integrally formed with the lead. Asthe anchoring arrangement is resorbed into the body of the patient, thesuture is released.

The anchoring arrangement 102 c of FIG. 3 includes a mass of resorbablematerial disposed on the lead 104. In at least some instances, thisanchoring arrangement can be anchored in position simply by thesurrounding tissue. Optionally, the shape of the anchoring arrangementcan be selected to prevent or resist rotations of the electrode leadand/or lateral or longitudinal movement of the lead when implanted inthe body. In some instances, a fastener, such as a suture or staple, canpenetrate the resorbable material of the anchoring arrangement 102 c toprovide further fixation for the lead 104. An another alternative, theanchoring arrangement 102 c can be adhesively attached to surroundingtissue. Any fastener or adhesive attachment is released upon resorbtionof the material of the anchoring arrangement.

FIGS. 4-7 illustrate another embodiment of an anchoring arrangement 202.The anchoring arrangement 202 is provided as a cuff upon which one ormore electrodes 206 (or sensors or catheter lumens) are disposed. Theelectrodes can be, for example, metal wires that are disposed on orwithin the material of the cuff. The electrodes 206 are (individually,collectively, or otherwise) coupled to a lead 204 that is connected to apulse generator (not shown) which provides electrical pulses along oneor more conductors 208 to the electrodes. As illustrated in FIG. 5, thecuff of the anchoring arrangement 202 can be positioned around a portion210 of the body, such as a nerve, artery, vein, tissue, or organ. Theanchoring arrangement 202 holds the electrodes 206 in place.

Preferably, the electrodes and conductors are made of a flexibleelectrically conducting material and can be a single strand or multiplestrands. Examples of suitable materials for the electrodes andconductors include stainless steel, platinum, iridium, titanium, and thelike. The electrodes and conductors can be uninsulated or insulated.Typically, those regions of the electrodes through which current is tobe provided directly to the tissue are uninsulated.

The cuff of the anchoring arrangement 202 is formed, at least in part,of resorbable material which is resorbed into the body of the patientover time leaving the electrodes 206, as illustrated in FIGS. 6 and 7.As described above, tissue may be encouraged to grow around theelectrodes or lead to stabilize the structure over time.

This embodiment can be modified by including one or more sensors ortransmitters, in addition to or as an alternative to the electrodes. Theembodiment can also be altered modified to include a catheter lumen thatextends through the lead to the cuff. The cuff supports the end portionof the catheter lumen with one or more openings in the catheter lumenfor providing the drug, medication, or other agent.

Another embodiment of an implantable device with an anchoringarrangement 302 is illustrated in FIGS. 8 and 9. The anchoringarrangement 302 is configured to be wrapped around a portion 310 of thebody of the patient, such as a nerve, vein, artery, organ, or othertissue, as illustrated in FIG. 8. The anchoring arrangement 302 can bewrapped in any way including in a helical manner. The electrodes 306 canbe carried on or in the material of the anchoring arrangement 302. Theelectrodes 306 are coupled to a lead 304 and conductors 308. Over time,the material of the anchoring arrangement is resorbed, as illustrated inFIG. 9, to leave the electrodes 306. This embodiment can be modified, asdescribed above, for use with a catheter, sensor, and/or transmitter.

The electrode leads, catheters, sensors, and transmitters describedherein are typically coupled to an implantable or external control unitas part of an implantable system or device. For example, an electrodelead can be coupled to an implantable pulse generator and a catheter canbe coupled to an implantable or external drug delivery pump.

The above specification, examples and data provide a description of themanufacture and use of the composition of the invention. Since manyembodiments of the invention can be made without departing from thespirit and scope of the invention, the invention also resides in theclaims hereinafter appended.

What is claimed and desired to be protected by Letter Patent of theUnited States is:
 1. An implantable device, comprising: a device bodyconfigured and arranged to be implanted proximate to selected tissue ina patient, the device body comprising a distal portion, a proximalportion, at least one electrode disposed on the distal portion of thedevice body, at least one terminal disposed on the proximal portion ofthe device body, and at least one conductor extending along the devicebody from the at least one electrode to the at least one terminal; andan anchoring unit disposed around a portion of the device body betweenthe at least one electrode and the at least one terminal, the anchoringunit configured and arranged for anchoring the device body in thepatient upon implantation, the anchoring unit comprising a ring-shapedunit forming, by itself, a closed loop defining a device openingconfigured and arranged for receiving a portion of the device body, thering-shaped unit formed from a resorbable material that resorbs into thepatient over a period of time after implantation, the resorption atleast partially releasing the at least one electrode from the anchoringunit while the device body is implanted in the patient, the anchoringunit configured and arranged such that the period of time of resorptionis sufficient to allow tissue ingrowth around the at least one electrodeto anchor the at least one electrode prior to release of the at leastone electrode due to at least a partial resorption of the anchoringunit, wherein the anchoring unit additionally defines at least oneclosed-loop anchoring opening extending therethrough, the anchoringopening configured and arranged for passage of at least one of at leastone suture or at least one staple, the at least one anchoring openingbeing separate and distinct from the device opening.
 2. The implantabledevice of claim 1, wherein the implantable device is one of apercutaneous lead or a paddle lead, and wherein the implantable lead isan electrode lead.
 3. The implantable device of claim 2, wherein theanchoring unit is configured and arranged for coupling the device bodyto tissue using at least one suture, wherein resorption of the anchoringunit into the patient releases the device body from the at least onesuture.
 4. The implantable device of claim 2, wherein the anchoring unitand the device body are configured and arranged for passage of a suturebetween the anchoring unit and the device body.
 5. The implantabledevice of claim 2, wherein the anchoring unit is configured and arrangedfor coupling the device body to tissue using at least one staple,wherein resorption of the anchoring unit into the patient releases thedevice body from the at least one staple.
 6. The implantable device ofclaim 2, wherein the anchoring unit is configured and arranged forgluing the device body to tissue using the anchoring unit, whereinresorption of the anchoring unit into the patient releases the devicebody from the glue.
 7. The implantable device of claim 2, wherein theanchoring unit is formed integrally with the device body.
 8. Theimplantable device of claim 2, wherein the anchoring unit is removablefrom the device body.
 9. The implantable device of claim 2, wherein theanchoring unit couples to the implantable device body by sliding theanchoring unit over at least a portion of the implantable device body.10. The implantable device of claim 2, wherein the device body isconfigured and arranged for explanation from the patient after theresorbable material is resorbed by the patient.
 11. The implantabledevice of claim 2, wherein the anchoring unit is disposed completelyaround the device body with the entire anchoring unit positioned betweenthe at least one electrode and the at least one terminal.
 12. A methodof implanting the stimulation system of claim 2, the method comprising:implanting the device body of the stimulation system into a patient;disposing the anchoring unit of the stimulation system around a portionof the device body between the at least one electrode and the at leastone terminal of the device body; and anchoring the anchoring unit to thepatient upon implantation with the device body disposed proximate toselected patient tissue.
 13. The method of claim 12, further comprisingremoving the device body after enough of the resorbable material isresorbed by the patient to at least partially release the at least oneelectrode from the anchoring unit.
 14. The method of claim 13, whereinresorption of the at least one anchoring unit fully releases the atleast one of the electrodes from the at least one anchoring unit. 15.The method of claim 12, wherein anchoring the anchoring unit to thepatient comprises suturing the device body to patient tissue using theanchoring unit.
 16. The implantable device of claim 2, wherein theanchoring unit has a width along a dimension of the anchoring unit thatis parallel with the closed loop defining the device opening, whereinthe anchoring unit has a thickness along a dimension of the anchoringunit that is normal to the closed loop defining the device opening, andwherein the width is larger than the thickness.
 17. A stimulation systemcomprising: the implantable device of claim 2; a control unit configuredand arranged for receiving the electrode lead of the implantable device;and a connector disposed on the control unit, the connector configuredand arranged to removably receive the proximal portion of the devicebody of the electrode lead.
 18. The stimulation system of claim 17,wherein the control unit is also implantable.
 19. The stimulation systemof claim 17, wherein the control unit comprises an implantable pulsegenerator, wherein, the implantable pulse generator provides electricalpulses along the at least one conductor of the implantable device to theat least one electrode of the implantable device.
 20. The stimulationsystem of claim 19, wherein the implantable pulse generator isconfigured and arranged for implantation at a location that is remotefrom the anchoring unit.